Well, its not official yet, but Microsoft's Windows 7 has now become the most widely used operating system. . . Windows 7 now has a strong 40.21% share of all desktop operating systems around the world whereas, the usage share of Windows XP has slipped to 38.64%. All this happened a couple of days back (in October). The rise in usage of Windows 7 and the drop in usage of Windows XP has been consistent since the time Windows 7 was first launched.

I would also concur that the web surfing statistics likely do not reflect the installed based.

Nevertheless, a few interesting twists:

i) Windows 7 has been globally encountered more often than Windows Vista for quite some time. In many areas, OS X is also more prevalent than Windows Vista.

ii) The shift to Windows 7 likely reflects hardware replacement.....the last systems build and sold with Windows XP (not as a downgrade from Vista) are roughly 3-1/2 to 4 years old. As application developers are likely coding for the more recent hardware/software platform, the older XP based systems are felt lagging (or simply breaks down and can't be repaired).

iii) It would be more informative if the statistics could be broken down into the Home vs. Professional versions of Windows XP and the Home/Home Premium vs. Professional/Ultimate versions of Windows 7. This would tell general public vs. corporate base.

iv) The low frequency of encounters of Linux based systems is rather puzzling - maybe the Linux users don't frequent the same sites as the rest of users?